WordWeb Online

1. Uneducated in general; lacking knowledge or sophistication
   "an ignorant man";
   - nescient, unlearned, unlettered
    
2. Uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field
   "she is ignorant of quantum mechanics";
   - illiterate
    
3. Unaware because of a lack of relevant information or knowledge
   "he was completely ignorant of the circumstances";
   - unknowledgeable, unknowing, unwitting
    
4. Showing no courtesy; rude
   - discourteous

See also: abrupt, brusk [non-standard], brusque, caddish, courtesy, curt, disrespectful, good manners, short, snippy [informal], unceremonious, unchivalrous, uneducated, ungallant, uninformed

Encyclopedia: Ignorant, Steve